IL13 Acts Directly on Gastric Epithelial Cells to Promote Metaplasia Development During Chronic Gastritis

Abstract

Interleukin 13 (IL13) is secreted by multiple subsets of immune cells and acts directly on the gastric epithelium to promote neck cell expansion and metaplasia. Mice with autoimmune gastritis lacking the IL13 receptor do not develop neck cell expansion or metaplasia, and neutralization of IL13 inhibits and reverses disease development during chronic gastritis. BACKGROUND & AIMS:It is well established that chronic inflammation promotes gastric cancer-associated metaplasia, but little is known regarding the mechanisms by which immune cells and cytokines regulate metaplastic cellular changes. The goals of this study were to identify interleukin 13 (IL13)-producing immune cells, determine the gastric epithelial cell response(s) to IL13, and establish the role(s) of IL13 in metaplasia development. METHODS:Experiments used an established mouse model of autoimmune gastritis (TxA23), TxA23xIl4ra Q9 -/mice, which develop gastritis but do not express the IL4/IL13-receptor subunit IL4Ra, and TxA23xIL13-YFP Q10 mice, which express yellow fluorescent protein in IL13-producing cells. Flow cytometry was used to measure IL13 secretion and identify IL13producing immune cells. Mouse and human gastric organoids were cultured with IL13 to determine epithelial cell response(s) to IL13. Single-cell RNA sequencing was performed on gastric epithelial cells from healthy and inflamed mouse stomachs. Mice with gastritis were administered IL13neutralizing antibodies and stomachs were analyzed by histopathology and immunofluorescence. RESULTS:We identified 6 unique subsets of IL13-producing immune cells in the inflamed stomach. Organoid cultures showed that IL13 acts directly on gastric epithelium to induce a metaplastic phenotype. IL4Ra-deficient mice did not progress to metaplasia. Single-cell RNA sequencing determined that gastric epithelial cells from IL4Ra-deficient mice up-regulated inflammatory genes but failed to up-regulate metaplasia-associated transcripts. Neutralization of IL13 significantly reduced and reversed metaplasia development in mice with gastritis.CONCLUSIONS: IL13 is made by a variety of immune cell subsets during chronic gastritis and promotes gastric cancer-associated metaplastic epithelial cell changes. Neutralization of IL13 reduces metaplasia severity during chronic gastritis.

Two Distinct Etiologies of Gastric Cancer: Infection and Autoimmunity

“…IL-17 and IFN-γ in this model have been found to induce parietal cell atrophy initiating pathology in the corpus of the stomach (Bockerstett et al, 2018;Osaki et al, 2019). The type two cytokine IL-13 was also found to have a profound impact on progressing gastric pathology beyond atrophic gastritis in TxA23 animals, driving metaplastic transformation in the tissue (Noto et al, 2021). These mice also show significant increases in pSTAT3 and IL-6, two molecules known to be associated with human carcinomas .…”

“…Remarkable similarities include a considerable lymphocytic infiltration with predominant Th1-and Th17-differentiated effectors and inflammation-responding epithelial cells upregulating MHC II molecules to aid in CD4 + T cell activation (Smythies et al, 2000;Shi et al, 2010;Archimandritis et al, 2000;D'Elios et al, 2001;Burman et al, 1992;. While type two cytokines, IL-4 and IL-13, are not responsible for initiating inflammation in response to either Hp or AIG, studies have found them to be critical for promoting severe metaplastic and even dysplastic lesions as disease progresses beyond gastritis (Marotti et al, 2008;Gabitass et al, 2011;Miska et al, 2018;Petersen et al, 2018;De Salvo et al, 2021;Noto et al, 2021). Cells like dendritic cells, macrophages, mast cells, and eosinophils have also been identified in both disease settings (Burman et al, 1992;Nakajima et al, 1997;Ninomiya et al, 2000;Suzuki et al, 2002;Hafsi et al, 2004;Moorchung et al, 2006;Khamri et al, 2010;Park et al, 2013;Bockerstett et al, 2020;Go et al, 2021).…”

Discovering Immune-Mediated Mechanisms of Gastric Carcinogenesis Through Single-Cell RNA Sequencing

“…This led to the hypothesis that IL-13 is driving M2 recruitment/ polarization in the gastric mucosa. IL-13 is thought to be produced by Th2 cells, but macrophages, mast cells, and ILC2s are also capable of producing IL-13, as observed in mouse models of gastric disease (49)(50)(51). Busada et al ( 2019) used a mouse model where precancerous gastric lesions were induced by eliminating androgen and glucocorticoid signaling, inflicting gastric inflammation and tissue damage (50,80).…”

“…Future scRNAseq work should compare SPEM arising out of other etiologies of gastritis, including the most common risk factor for gastric cancer, Helicobacter pylori infection (5). Noto et al ( 2021) also found that IL-4 and/or IL-13, produced by mast cells or ILC2s, were required to drive the epithelial cell transition from precursor inflamed epithelial cells toward SPEM (49). Interestingly, in autoimmune animals that lack the IL-4/IL-13 receptors, making both epithelial and immune cells unable to respond to signaling, inflamed precursor epithelial cells arise but fail to progress to SPEM.…”

“…Others transcriptionally profiled "liquid biopsies" of metastatic ascites fluid taken from gastric cancer patients (44,45). Realizing that human tissues are difficult to procure, some created laboratory models of gastric diseases, either as in vivo mouse settings or in vitro gastric organoids (35,(46)(47)(48)(49)(50)(51)(52)(53)(54)(55). Beyond the purview of this review, other valuable scRNAseq datasets also have been generated from healthy gastric tissues (56)(57)(58)(59).…”